Is / was "OTTO" typically used to mean gasoline in Germany or was this just slang created by US soldiers?
And yes, were not people still using the "visible" gas pumps with the glass tank on top during the war years? Metering pumps like these were not yet invented????

Not the same, but it reminds me of this one preserved in Sweden :
On a side note, the Plus Model one has a "rauchen verboten" sign visible behind the right pump. The logo looks like the prewar one :
H.P.